1. Field of the Invention
The present invention relates to a power generating system integrally provided with a gas turbine and a solid electrolyte type fuel cell.
2. Description of the Related Art
A hybrid power system comprising a combination of a turbo-machine and a fuel cell is described in the published Japanese translation No. 2001-516935 of PCT application No. PCT/US98/19219. The turbo-machine is adapted to drive a generator by rotating a power turbine by a high-pressure gas generated by burning a fuel in a combustor, thereby generating electricity, and the fuel cell is adapted to cause the reaction between fuel and air passing through a compressor and a recuperator to be heated, thereby generating electricity.
A vehicle including a fuel cell and a generator driven by a gas turbine engine is described in U.S. Pat. No. 6,213,234. A reduction of fuel consumption can be provided without excessive increase in the size of the fuel cell by supplying about 50% of the maximum electric power required to drive the vehicle from the fuel cell. When the electric power required by the vehicle is small, the fuel cell effectively supplies all or most of the required electric power.
There is a vehicle described in U.S. Pat. No. 6,255,010, in which a power generating system including a gas turbine engine, a fuel cell and a generator is accommodated in a common pressure vessel and operated in a pressurized state.
If the gas turbine engine and the fuel cell are disposed separately, the size of the entire system disadvantageously increases, and hence it is conceived that the fuel cell is accommodated in a casing of the gas turbine to provide compactness. However, even if the fuel cell is combined simply with the gas turbine engine, the compactness of the system is limited. Moreover, it is difficult to effectively absorb the thermal expansions of the gas turbine engine and the fuel cell heated to a high temperature of several hundred degree during operation of the power generating system, leading to a possibility that the thermal stresses of the gas turbine engine and the fuel cell are increased to reduce power generating efficiency and durability of the power generating system.
In order to reduce the fuel consumption in a power generating system integrally including a gas turbine engine and a solid electrolyte type fuel cell to enhance the power generating efficiency, it is required to effectively utilize waste heat of the power generating system. However, it is difficult to effectively utilize the waste heat only by disposing the gas turbine engine and the solid electrolyte type fuel cell with a distance therebetween, or combining the fuel cell simply with the gas turbine engine.
In addition, in the power generating system integrally provided with the gas turbine engine and the solid electrolyte type fuel cell, when the solid electrolyte type fuel cell is activated by utilizing the waste heat generated by a burner of the gas turbine engine, it is difficult to effectively utilize the waste heat only by disposing the gas turbine engine and the solid electrolyte type fuel cell with a distance between them, or combining the fuel cell simply with the gas turbine engine.